/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrAppliedClip_DEFINED
#define GrAppliedClip_DEFINED

#include "src/gpu/ganesh/GrFragmentProcessor.h"
#include "src/gpu/ganesh/GrScissorState.h"
#include "src/gpu/ganesh/GrWindowRectsState.h"

#include "src/core/SkClipStack.h"


/* *
 * Produced by GrHardClip. It provides a set of modifications to the hardware drawing state that
 * implement the clip.
 */
class GrAppliedHardClip {
public:
    static const GrAppliedHardClip &Disabled()
    {
        // The size doesn't really matter here since it's returned as const& so an actual scissor
        // will never be set on it, and applied clips are not used to query or bounds test like
        // the GrClip is.
        static const GrAppliedHardClip kDisabled({ 1 << 29, 1 << 29 });
        return kDisabled;
    }

    GrAppliedHardClip(const SkISize &rtDims) : fScissorState(rtDims) {}
    GrAppliedHardClip(const SkISize &logicalRTDims, const SkISize &backingStoreDims) : fScissorState(backingStoreDims)
    {
        fScissorState.set(SkIRect::MakeSize(logicalRTDims));
    }

    GrAppliedHardClip(GrAppliedHardClip &&that) = default;
    explicit GrAppliedHardClip(const GrAppliedHardClip &) = default;

    const GrScissorState &scissorState() const
    {
        return fScissorState;
    }
    const GrWindowRectsState &windowRectsState() const
    {
        return fWindowRectsState;
    }
    uint32_t stencilStackID() const
    {
        return fStencilStackID;
    }
    bool hasStencilClip() const
    {
        return SkClipStack::kInvalidGenID != fStencilStackID;
    }

    /* *
     * Intersects the applied clip with the provided rect. Returns false if the draw became empty.
     * 'clippedDrawBounds' will be intersected with 'irect'. This returns false if the clip becomes
     * empty or the draw no longer intersects the clip. In either case the draw can be skipped.
     */
    bool addScissor(const SkIRect &irect, SkRect *clippedDrawBounds)
    {
        return fScissorState.intersect(irect) && clippedDrawBounds->intersect(SkRect::Make(irect));
    }

    void setScissor(const SkIRect &irect)
    {
        fScissorState.set(irect);
    }

    void addWindowRectangles(const GrWindowRectsState &windowState)
    {
        SkASSERT(!fWindowRectsState.enabled());
        fWindowRectsState = windowState;
    }

    void addWindowRectangles(const GrWindowRectangles &windows, GrWindowRectsState::Mode mode)
    {
        SkASSERT(!fWindowRectsState.enabled());
        fWindowRectsState.set(windows, mode);
    }

    void addStencilClip(uint32_t stencilStackID)
    {
        SkASSERT(SkClipStack::kInvalidGenID == fStencilStackID);
        fStencilStackID = stencilStackID;
    }

    bool doesClip() const
    {
        return fScissorState.enabled() || this->hasStencilClip() || fWindowRectsState.enabled();
    }

    bool operator == (const GrAppliedHardClip &that) const
    {
        return fScissorState == that.fScissorState && fWindowRectsState == that.fWindowRectsState &&
            fStencilStackID == that.fStencilStackID;
    }
    bool operator != (const GrAppliedHardClip &that) const
    {
        return !(*this == that);
    }

private:
    GrScissorState fScissorState;
    GrWindowRectsState fWindowRectsState;
    uint32_t fStencilStackID = SkClipStack::kInvalidGenID;
};

/* *
 * Produced by GrClip. It provides a set of modifications to GrPipeline that implement the clip.
 */
class GrAppliedClip {
public:
    static GrAppliedClip Disabled()
    {
        return GrAppliedClip({ 1 << 29, 1 << 29 });
    }

    GrAppliedClip(const SkISize &rtDims) : fHardClip(rtDims) {}
    GrAppliedClip(const SkISize &logicalRTDims, const SkISize &backingStoreDims)
        : fHardClip(logicalRTDims, backingStoreDims)
    {}

    GrAppliedClip(GrAppliedClip &&that) = default;
    GrAppliedClip(const GrAppliedClip &) = delete;

    const GrScissorState &scissorState() const
    {
        return fHardClip.scissorState();
    }
    const GrWindowRectsState &windowRectsState() const
    {
        return fHardClip.windowRectsState();
    }
    uint32_t stencilStackID() const
    {
        return fHardClip.stencilStackID();
    }
    bool hasStencilClip() const
    {
        return fHardClip.hasStencilClip();
    }
    int hasCoverageFragmentProcessor() const
    {
        return fCoverageFP != nullptr;
    }
    const GrFragmentProcessor *coverageFragmentProcessor() const
    {
        SkASSERT(fCoverageFP != nullptr);
        return fCoverageFP.get();
    }
    std::unique_ptr<GrFragmentProcessor> detachCoverageFragmentProcessor()
    {
        SkASSERT(fCoverageFP != nullptr);
        return std::move(fCoverageFP);
    }

    const GrAppliedHardClip &hardClip() const
    {
        return fHardClip;
    }
    GrAppliedHardClip &hardClip()
    {
        return fHardClip;
    }

    void addCoverageFP(std::unique_ptr<GrFragmentProcessor> fp)
    {
        if (fCoverageFP == nullptr) {
            fCoverageFP = std::move(fp);
        } else {
            // Compose this coverage FP with the previously-added coverage.
            fCoverageFP = GrFragmentProcessor::Compose(std::move(fp), std::move(fCoverageFP));
        }
    }

    bool doesClip() const
    {
        return fHardClip.doesClip() || fCoverageFP != nullptr;
    }

    bool operator == (const GrAppliedClip &that) const
    {
        if (fHardClip != that.fHardClip ||
            this->hasCoverageFragmentProcessor() != that.hasCoverageFragmentProcessor()) {
            return false;
        }
        if (fCoverageFP != nullptr && !fCoverageFP->isEqual(*that.fCoverageFP)) {
            return false;
        }
        return true;
    }
    bool operator != (const GrAppliedClip &that) const
    {
        return !(*this == that);
    }

    void visitProxies(const GrVisitProxyFunc &func) const
    {
        if (fCoverageFP != nullptr) {
            fCoverageFP->visitProxies(func);
        }
    }

private:
    GrAppliedHardClip fHardClip;
    std::unique_ptr<GrFragmentProcessor> fCoverageFP;
};

#endif
